<!DOCTYPE html>
<html lang="en">
	<head>
		<title>three.js webgl - layers</title>
		<meta charset="utf-8">
		<meta name="viewport" content="width=device-width, user-scalable=no, minimum-scale=1.0, maximum-scale=1.0">
		<link type="text/css" rel="stylesheet" href="main.css">
		<style>
			body {
				background-color: #f0f0f0;
				color: #444;
			}
			a {
				color: #08f;
			}
		</style>
	</head>
	<body>

		<div id="info">
			<a href="https://threejs.org" target="_blank" rel="noopener">three.js</a> - webgl layers
		</div>

		<script type="importmap">
			{
				"imports": {
					"three": "../build/three.module.js",
					"three/addons/": "./jsm/"
				}
			}
		</script>

		<script type="module">

			import * as THREE from 'three';

			import Stats from 'three/addons/libs/stats.module.js';
			import { GUI } from 'three/addons/libs/lil-gui.module.min.js';

			let container, stats;
			let camera, scene, renderer;

			let theta = 0;
			const radius = 5;

			init();

			function init() {

				container = document.createElement( 'div' );
				document.body.appendChild( container );

				camera = new THREE.PerspectiveCamera( 70, window.innerWidth / window.innerHeight, 0.1, 100 );
				camera.layers.enable( 0 ); // enabled by default
				camera.layers.enable( 1 );
				camera.layers.enable( 2 );

				scene = new THREE.Scene();
				scene.background = new THREE.Color( 0xf0f0f0 );

				const light = new THREE.PointLight( 0xffffff, 3, 0, 0 );
				light.layers.enable( 0 );
				light.layers.enable( 1 );
				light.layers.enable( 2 );

				scene.add( camera );
				camera.add( light );

				const colors = [ 0xff0000, 0x00ff00, 0x0000ff ];
				const geometry = new THREE.BoxGeometry();

				for ( let i = 0; i < 300; i ++ ) {

					const layer = ( i % 3 );

					const object = new THREE.Mesh( geometry, new THREE.MeshLambertMaterial( { color: colors[ layer ] } ) );

					object.position.x = Math.random() * 40 - 20;
					object.position.y = Math.random() * 40 - 20;
					object.position.z = Math.random() * 40 - 20;

					object.rotation.x = Math.random() * 2 * Math.PI;
					object.rotation.y = Math.random() * 2 * Math.PI;
					object.rotation.z = Math.random() * 2 * Math.PI;

					object.scale.x = Math.random() + 0.5;
					object.scale.y = Math.random() + 0.5;
					object.scale.z = Math.random() + 0.5;

					object.layers.set( layer );

					scene.add( object );

				}

				renderer = new THREE.WebGLRenderer( { antialias: true } );
				renderer.setPixelRatio( window.devicePixelRatio );
				renderer.setSize( window.innerWidth, window.innerHeight );
				renderer.setAnimationLoop( animate );
				container.appendChild( renderer.domElement );

				stats = new Stats();
				container.appendChild( stats.dom );

				const layers = {

					'toggle red': function () {

						camera.layers.toggle( 0 );

					},

					'toggle green': function () {

						camera.layers.toggle( 1 );

					},

					'toggle blue': function () {

						camera.layers.toggle( 2 );

					},

					'enable all': function () {

						camera.layers.enableAll();

					},

					'disable all': function () {

						camera.layers.disableAll();

					}

				};

				//
				// Init gui
				const gui = new GUI();
				gui.add( layers, 'toggle red' );
				gui.add( layers, 'toggle green' );
				gui.add( layers, 'toggle blue' );
				gui.add( layers, 'enable all' );
				gui.add( layers, 'disable all' );

				window.addEventListener( 'resize', onWindowResize );

			}

			function onWindowResize() {

				camera.aspect = window.innerWidth / window.innerHeight;
				camera.updateProjectionMatrix();

				renderer.setSize( window.innerWidth, window.innerHeight );

			}

			//

			function animate() {

				render();
				stats.update();

			}

			function render() {

				theta += 0.1;

				camera.position.x = radius * Math.sin( THREE.MathUtils.degToRad( theta ) );
				camera.position.y = radius * Math.sin( THREE.MathUtils.degToRad( theta ) );
				camera.position.z = radius * Math.cos( THREE.MathUtils.degToRad( theta ) );
				camera.lookAt( scene.position );

				renderer.render( scene, camera );

			}

		</script>

	</body>
</html>
